If you thought the power of TV to break bands had died in the face of the internet and X Factor humdrum, you were wrong. Synth-pop maestros Future Islands – the biggest band you’ve never heard of, yet – hit Grumpy Cat levels of viral fame after they appeared on Late Show with David Letterman.

Their peculiar performance of Seasons (Waiting On You) has notched up more than 1.4 million YouTube views (below) – second only to Letterman’s resignation speech as the most-watched clip from the chat show titan’s history. Not bad for an anomaly like Future Islands.

It was polarising – imagine an impassioned, chest-thumping hybrid of Morrissey and Simple Minds’ Jim Kerr with Northern Soul dance moves fronting the geek chic of New Order, and you’re almost there – but in typical Future Islands fashion it provoked a reaction.

The Letterman buzz aside, this North Carolina-via-Baltimore three-piece – made up of Samuel T Herring, Gerrit Welmers and William Cashion – are no spring chickens. Latest album Singles is their fourth LP, arriving after a near-decade long slog of touring and numerous small-scale releases.

Now, as the spotlight shines bright, vocalist Samuel T Herring speaks to The Big Issue about being the most talked-about band in the world, why he avoids doctors and dressing up as The King…

Letterman looked genuinely delighted by your performance. How have things gone since?

It’s been crazy. There was pressure and excitement in doing Letterman. We were nervous but we just went out and did what we do best. I’m still confused, but I’m just glad it’s happening. We’ve definitely noticed a turn in the amount of people finding out about us and it’s exciting. More people are coming out to shows after Letterman but we haven’t really changed anything; we’re still touring in the same little van, cruising around the country.

How does it feel to become the most hyped band in the world in a heartbeat?

A lot of hard work has gone into this. We’ve been doing this for 11 years now, eight as Future Islands, and there’s a long history that defines who we are. Tonight in Montana is our 813th show as Future Islands. Dedicating ourselves to touring is a big part of what we’re all about, but towards the end of 2012 we’d been on the road for almost five years and we were so tired. We had to pull ourselves back to record Singles.

We’ve been doing this for 11 years now, eight as Future Islands, and there’s a long history that defines who we are

Wasn’t it a bit risky recording Singles without a label already in place?

I don’t think so. We didn’t want anyone else’s hands on it. We didn’t want a contract hanging over our heads or anyone dictating what they thought our album should be like. We just wanted to be able to create something fully on our own without interference or deadlines, and we’re very proud with how it’s turned out.

What were you all doing before Future Islands?

I had been working at Domino’s pizza and was laying concrete. Gerrit was working as a bartender at a Hilton hotel and William at an art store. We all lived in different cities in North Carolina but moved to Baltimore and really put everything into Future Islands in 2008.

You have a very unique, animated performance style. What artists influenced the young Sam Herring?

I was pretty inspired by early soul musicians like Sammy Davis, Marvin Gaye. I used to do mean James Brown and Elvis impersonations when I was young. My mum had all the Elton John records. I loved Madman Across the Water and Goodbye Yellow Brick Road. Then Danzig and The Misfits were big for me. Performing for me is about trying to connect with the music, to bring out something physical. I like to do that with my body and with my movement. It creates a reaction, it makes an impression. I believe you gotta give everything you got. We aren’t infinite. Put everything on the line every night.

Do you need to be careful in looking after your voice with those strong, deep vocals?

I definitely don’t want a doctor looking down my throat. I did a lot of damage to my voice early on, I never took good care of it. If I see a doctor he’ll probably tell me to stop singing.

Has this huge increase in exposure changed your perception of success?

Our expectations are always very high and that’s why we’ve come a long way. I remember 4AD asking if we were ready for the next step, which is kind of funny. We’ve been ready for a long time. Just give us a stage and we will work. We believe in what we do and it’s easy to put everything into that. We want to affect people.

Singles is out now on 4AD. Future Islands tour the UK in June and November: future-islands.com

Future Islands

Future Islands: “My body moves creates a reaction”